B.R.S.M. The road to Tet. Lett. Is paved with good intentions

17Aug/112

(–)-N-Methylwelwitindolinone C Isothiocyanate

Update: 13/09/11. I have reworded the introduction considerably as the original version of this paragraph described work by Rawal and coworkers in this area unfairly. Having reread the papers and what I'd written I couldn't leave things as they were. The original text can be found in [5] at the end of the article.

Sorry things have been so quiet around here lately - moving out of the flat I've lived in for the past three years, having no internet and applying for conferences have made blogging tricky. I was a bit worried that someone'd beat me to this as it's such a nice bit of work, and Tot. Syn. did on Sunday, but I'd mostly finished this by then, so here's my take anyway.

Total Synthesis of (–)-N-Methylwelwitindolinone C Isothiocyanate

Garg et al., J. Am. Chem. Soc., 2011, ASAP; [PDF][SI][GROUP]

DOI: 10.1021/ja206538k

There's been a lot of interest in these unusual looking natural products in the past decade with publications from Wood, Trost, Baran, Simpkins, Martin and Rawal all appearing in the literature. Credit for the first total synthesis of a member of this family goes to Rawal and coworkers, who reported a neat route to racemic N-methylwelwitindolinone D isonitrile back in March of this year, unfortunately before I'd started this blog.[1,2] This paper by Garg describes the first synthesis of N-methylwelwitindolinone C isothiocyanate to date, using a chiral pool based approach from (S)-carvone, and also contains lots of interesting chemistry.

Filed under: Current Literature, Total Synthesis | 6,136 views | 3 comments Continue reading
17Jul/114

(+)-Omphadiol

A second post this weekend - you guys are lucky the weather is awful here!

Total Synthesis of (+)-Omphadiol

Romo et al., Angew. Chem. Int. Ed., 2011, Early View; [PDF] [SI] [GROUP]

DOI: 10.1002/anie.201102289

Omphadiol is an africanane sesquiterpene isolated for the first time in 2000 from a basidiomycete. No-one knows what it does because of the small amounts isolated, but structurally similar sesqui- and diterpenes exhibit various biological activities including antiviral, anti-inflammatory and anti proliferative effects. It’s also got an interesting 5-7-3 ring system and 6 contiguous stereocentres around the ever popular trans-hydroazulene core. That notwithstanding, it took Daniel Romo and coworkers at Texas A&M University just 10 steps (and not a single protecting group) to prepare the natural product stereoselectively from (R)-carvone via a bicyclic b-lactone intermediate. 

Filed under: Current Literature, Serious, Total Synthesis | 10,224 views | 4 comments Continue reading